Determination of bedaquiline in human serum using liquid chromatography-tandem mass spectrometry.

Bedaquiline, a diarylquinoline for the treatment of multidrug-resistant tuberculosis (TB), relies on exposure-dependent killing. As data on drug exposure in specific populations are scarce, pharmacokinetic studies may be of interest. No simple and robust validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been reported to date.

Hospital-based cluster randomised controlled trial to assess effects of a multi-faceted programme on influenza vaccine coverage among hospital healthcare workers and nosocomial influenza in the Netherlands, 2009 to 2011.

Nosocomial influenza is a large burden in hospitals. Despite recommendations from the World Health Organization to vaccinate healthcare workers against influenza, vaccine uptake remains low in most European countries. We performed a pragmatic cluster randomised controlled trial in order to assess the effects of implementing a multi-faceted influenza immunisation programme on vaccine coverage in hospital healthcare workers (HCWs) and on in-patient morbidity.

Lipase A gene transcription in Pseudomonas alcaligenes is under control of RNA polymerase σ54 and response regulator LipR.

Initial analysis has shown that the transcription of the Pseudomonas alcaligenes lipA gene, which encodes an extracellular lipase, is governed by the LipQR two-component system consisting of sensor kinase LipQ and DNA-binding regulator LipR. This study further analyzes lipA gene expression and demonstrates that the RNA polymerase σ54 is involved in the transcription. Purified LipR has an ATPase activity that is stimulated by the presence of lipA promoter DNA.

Heterologous production of Escherichia coli penicillin G acylase in Pseudomonas aeruginosa.

Penicillin G acylase (PGA) is a widely studied bacterial enzyme of great industrial importance. Since its overproduction in the original organisms is mostly limited to the intracellular bacterial spaces which may lead to aggregation and cell toxicity, we have set out to explore the host organism Pseudomonas aeruginosa that possesses the Xcp machinery for secretion of folded proteins to the extracellular medium. We have made fusion proteins, consisting of Pseudomonas Sec- or Tat-specific signal peptides, the elastase propeptide and the mature penicillin G acylase.

Phage display of an intracellular carboxylesterase of Bacillus subtilis: comparison of Sec and Tat pathway export capabilities.

Using the phage display technology, a protein can be displayed at the surface of bacteriophages as a fusion to one of the phage coat proteins. Here we describe development of this method for fusion of an intracellular carboxylesterase of Bacillus subtilis to the phage minor coat protein g3p. The carboxylesterase gene was cloned in the g3p-based phagemid pCANTAB 5E upstream of the sequence encoding phage g3p and downstream of a signal peptide-encoding sequence.

High throughput therapeutic drug monitoring of clozapine and metabolites in serum by on-line coupling of solid phase extraction with liquid chromatography-mass spectrometry.

The characteristics of automated on-line solid phase extraction with liquid chromatography-mass spectrometry (SPE-LC-MS) are very amenable for flexibility and throughput in therapeutic drug monitoring (TDM). We demonstrate this concept of automated, on-line SPE-LC-MS for the analysis of clozapine and metabolites (desmethylclozapine and clozapine-N-oxide) in serum. Method development, optimisation and validation are described and a comparison with previously published methods for the determination of clozapine and metabolites in serum and plasma is made.

Methodological advances in the discovery of protein and peptide disease markers.

The quest for biomarkers has seen a renaissance due to the application of newly developed separation methodologies and advances in biomolecular mass spectrometry. It can be argued that each disease influences the physiology of an organism and that these changes should be measurable. Many diagnostic and therapeutic decisions are supported by measurable biochemical or cellular changes in plasma, serum or urine but it is unquestionable that there is a great lack in better markers for early disease detection and prevention.

Effects of microdialysis catheter insertion into the subcutaneous adipose tissue assessed by the SCGM1 system.

To monitor glucose in patients with diabetes continuously a microdialysis-based glucose sensor system (SCGM1 System, Roche Diagnostics GmbH, Mannheim, Germany) is under clinical development. This system allows monitoring of glucose levels in the subcutaneous interstitial fluid of patients with diabetes for a maximum duration of up to 120 h. The aim of the study was to determine the effect of microdialysis catheter insertion on the stability of the SCGM1 System glucose sensor signal.

A model for transport of glucose in adipose tissue to a microdialysis probe.

A model is presented, describing diffusion of solutes (as glucose) through adipose tissue. The model is based on the well-known extraction equation for diffusion across capillary walls or across the membrane of microdialysis probes, but adapted for use in adipose tissue. Arguments are presented for a simple scheme in which the mean capillary concentration of a solute (i.

Dopamine D(2) activity of R-(-)-apomorphine and selected analogs: a microdialysis study.

In the present study, R-(-)-apomorphine and three of its analogs were studied for their potency in decreasing the release of dopamine in the striatum after subcutaneous administration and for their oral bioavailability using the microdialysis technique in freely moving rats. The analogs R-(-)-N-n-propylnorapomorphine and R-(-)-11-hydroxy-N-n-propylnoraporphine displayed a higher potency than R-(-)-apomorphine in decreasing the release of dopamine in the striatum. A high dose of R-(-)-11-hydroxyaporphine, a dopamine D(2) receptor partial agonist, had a small effect on the release of dopamine in the striatum.

Microdialysis of glucose in subcutaneous adipose tissue up to 3 weeks in healthy volunteers.

Objective: To measure possible changes in dialysate glucose concentrations over time, to validate the diffusional model for glucose transport from tissue to the probe, and to evaluate the actual glucose concentration in adipose tissue.

Research Design And Methods: Glucose concentrations in the subcutaneous adipose tissue of five healthy subjects (age 25 +/- 2.7 years, BMI 23.

Covalent and noncovalent protein binding of drugs: implications for hepatic clearance, storage, and cell-specific drug delivery.

This review deals with the mechanisms by which the liver disposes of drugs that are covalently or noncovalently associated with proteins. Many drugs bind to plasma proteins such as albumin (mainly anionic compounds) and alpha 1-acid glycoprotein (cationic compounds). Nevertheless, the liver is able to clear such drugs efficiently from the circulation because of intrahepatic dissociation of the drug-protein complex.